As far as the bomber goes....
The B-52 is just a bomb truck. Why not buy some 747s, 767s, 777s, or 787s (depending on how much you want to pay and the capability you want to have), put some bomb bays in them, hardpoints on them, electronics and other goodies on the inside, and call it the B-52 replacement? Sure its not perfect, and would require some reworking and modification of the airframe, but you now have a cheap, off the shelf, immensely reliable, available today, subsonic non-stealth bomber. Save the B-1s and B-2s for the more specialized stuff.
If you pick the 767, you now also have commonality with the KC-767 (if that ever shows up) too. Heck, put some detachable refueling equipment on it and some fuel tanks in the bomb bays and let the bomber also be the new tanker. Put a cargo door on it and let it carry a lot of the palletized cargo thats currently being carried around by much more expensive C-17s. Equip it to have other electronics and equipment put in the bomb bays, main deck, or hardpoints and you can replace a lot of the specialized -135 variants running around too.
What it all comes down to is that for many of these jobs, all you really need is a medium-large aircraft that can carry a significant payload cheaply, reliably, safely, over a respectable distance. This aircraft doesn't have to be a new design... Boeing has gotten pretty good at designing airplanes that do just that. Everything beyond that is just what you decide to load onto it that day. Sure, its not going to be as perfect as a special new build design for that specific mission, but we could have it tomorrow instead of 20 years from now, and at a quarter of the cost.
Save the very expensive and specialized aircraft we have in small numbers (B-1, B-2, C-17, KC-10, etc) for when a mission requires its capabilities.